Inclosed electric fuse.



R. C. COLE.

INCLOSED ELECTRK) FUSE. APPUC'ATIONFILED JuLY 28,1915.

} 1,235,555. PatentedAug. 7,1917.

INVEN TOR.

A TTORNE Y.

to rotated on its axis 90.

5 Fig. 5 is a side a etcr and length.

ii. .JA.

ROBERT C. COLE, F EABTFGRB, CGIQ'NECTICUT, ASSIGNOR T0 THE JQHNS-PRATT CEM- ZANY,

OF HARTFORD, SGTMIEFECTICUT,

A CORPORATION OF CGNNEGTICUT.

JTGLQSED ELECTRIC FUSE.

To all whom it may concern Be it known that 1, ROBERT C. Conn, a citizen of the United States, residing at Hartford, in the county of Ha tford. and

State of Connecticut, have invented a new and useful Improvement in Inclcsed Electric Fuses, of which the following is a specification.

This invention relates to the construction of inclosed fuses of the knife blade terminal t e.

The object of the invention is to construct an efiicient fuse having a minimum amount of metal, which is composed of parts that can be manufactured very cheaply and assembled in proper condition for the best service very easily, and that can be packed with insulating filler very quickly by any one without liability of injuring the fusible element.

In attaining this end the casing is formed of an insulating tube with short metallic caps closing the ends. Each exterior knife blade terminal and integral interior link terminal is secured to a yoke that is fastened in place by screws which pass transversely through the walls of the tube into the yoke. The caps are secured in place on the ends of the tube by screws that pass longitudinally of the tube through the caps into the yokes, and these screws are utilized to aline the exterior terminals, and cause the side screws to be bound and held against accidental displacement as well as to secure the caps in place.

Figure 1 of the accompanying drawings 1s a side View with one end cut in longitudinal section of a fuse which embodies the inven tion.

Fig. 2 is a similar view with the fuse Fig. 3 is a view looking at one end of the fuse.

Fig. 4 is a view looking at the end with the cap removed.

view of one of the conducting terminals and the anchor yoke to which it is connected.

The casing of the fuse is formed of a. section of insulating tube 1 of suitable diam- Each exterior terminal or knife blade 2 with its integral interior or link terminal 3 is fastened to the end of a yoke 4, preferably by heading over the studs 5 which extend from one end of the blade 5 through perforations in the end of the yoke.

Specification of Letters Patent.

Serial No. 111,787.

Each yoke is retained in place in the end of the tube by screws 5 that pass radially through perforations in the sides of the tube into threaded perforations in the limbs of the yoke. to shape from steel. or brass with a short flange of a size to fit the end of the tube and with a slot in the end of a size that fits the knife blade. Each cap is held in place, after it has been slipped over the knife blade and onto the end of the tube, by screws 8 that pass axially of the tube through perforations in the end of the cap into threaded perforations in the end of the yoke. A screen washer 9 is fitted in the bottom of each cap before the cap is placed on the end of the tube and secured to the yoke. This screen is desirably made of canvas or other woven fabric and is designed to permit the escape of air or gas from the interior of the tube through vent perforations 10 inthe end of the cap but prevent the powdered or granulated condensing filler 11 from leaking or being blown out from the tube. One or more links 12 of fusible 'metal having the required capacity have their ends secured to the interior terminals of the knife lades.

- In assembling this structure the fusible link connected between the terminals, which have been secured to the yokes, is inserted into the tube. The yokes are then held by turning into them the. screws that extend radially' through the sides of the tube. After the cap at one end is put over the knife blade and onto the end of the tube and is secured by the screws that extend lengthwise of the tube, the casing is filled with loose insulating material of the desired nature which is employed to condense the gases evolved by the volatilization of the metal when the fus is blown. After the tube has been filled the other cap is secured in place.

The caps employed with this fuse are very short and each is made of a single stain ing. The blades are pivotally held by the side screws that pass into the yokes and are roughly alined when the caps are placed on the ends of the tube. The blades can be accurately alined by drawing the yokes from one side or the other by means of the end screws which fasten the caps to the yokes. The screen washers are clamped between the caps and the ends of the tube and the yokes So as to prevent any accidental sifting out of Each end cap 7 may be stamped the filling and they also beside acting as vent screens, form cushions which permit the yokes to be drawn by the end-screws more orcept one cap before the fillihg is put in. As

a result of this the filling may be packed in without danger of buckling, or stretching,

or breaking, the fusible element. With the short caps permitted ,by this construction the surface .insulation on the fuse is increased. Furthermore, with the short caps there is less metal for the circulation of eddy currents whichparticularly-, if the caps are stamped from brass and the fuse is used on an alternating current systemtend to cause heating. The end screws passing through the caps draw out the yokes and cause the side screws to bind so as to eliminate the liability of their working outv accidentally.

If desired this fuse can be easily renewed, after being blown, and yetv it can be sealed by placing a label 13 as indicated in Fig. 2 over the side screws so as to readily indicate if those screws have been removed and the terminals taken out for the insertion of a new fusible element.

I claim as my invention:

1.-A fuse havin a casing formed of an insulating tubean short metal caps at the ends of the tube, knife blade terminals extending through the caps, yokes secured to said terminals within the casing, headed screws passing radially through the sides of memes the tube intothe yokes hear their inner ends in line with the edges of said blades, and

headed. screws passing axially of the tube through the ca s and into the bases of the yokes on each s de of said blades.

2. A fuse comprising an insulating tube, yokes in the interior at the ends of the tube, headed screws passin radially through the sides of the-tube in t e yokes near their inner ends, knife blade terminals secured to and extending through the yokes, a fusible the tube into the yokes, knife-blade terminals secured'to and extending through the yokes, a fusible element connecting the inner e s of said terminals, granular material filling the tube and surrounding the fusible element, perforated caps fitting the endsgof the tube, venting screens interposed between the inside of the caps and the ends of the tube and the ends 0 the yokes, and screws extending axially of the tube through the caps and screens into the yokes.

ROBERT 0. CODE.

I copies of this patent may be obtained for five cents. each, by addressing the "Commissioner of Patents,

Waiiflngton, I). 0. 

